Photoacoustic Tool to Improve Visualization and Success Rates in Sacral Neural Modulation Lead Placement

In this Phase I SBIR, Actuated Medical, Inc. (AMI) will develop and demonstrate the feasibility of a Photoacoustic Visualizer (PAV) system for greatly improving implantation accuracy of sacral neurostimulation (SNS) leads for better outcomes with people with bladder (urinary) or bowel incontinence. The system will enable ‘through-the-needle visualization’ and guidance control to direct SNS leads adjacent to the sacral nerve. This phase culminates with an in vivo preclinical demonstration of visualization and placement feasibility at the Penn State Milton S. Hershey Medical Center. Unmet Need: Loss of bladder or bowel control, or urinary or bowel incontinence, is an embarrassing and debilitating condition that greatly impacts the daily life of those affected. Over the continuum of severity, incontinence is estimated to affect between 18M and 80M people and incur healthcare costs over $90B in the U.S. alone, with many reports acknowledging low estimates because people do not want to be associated with the social stigma. Conservative treatments are cumbersome or produce side effects, and up to two-thirds of people stop treatment within a year. Because incontinence is ultimately caused by lack of muscle control, the sacral nerve, which controls the bladder and other pelvic muscles, has been a focus. Direct neurostimulation of the sacral nerve via an implant has become a viable option in otherwise intractable cases. After successful implantation, long-term effectiveness of 50-80% has been reported, however, initial implantation success has been reported as low as 24%. A significant factor in failure is inadequate proximity between the nerve and electrodes in the stimulation lead, which is placed in a multi-step, minimally invasive surgical procedure that requires high precision but has limited means of imaging to guide through the S3 foramen of the sacrum. Muscle stimulation checks are the primary means of confirmation for alignment of the lead with the curved nerve path. Representative cadaver studies have shown separations up to 16 mm, too far for clinical efficacy. In this SBIR project, AMI is leveraging its experience in neuroscience, ultrasound and photoacoustics (PA), and catheters/stems for medical devices to develop the PAV, a unique PA-based guidance system that aligns with standard SNS lead implantation techniques. The PAV integrates optical transmit and ultrasound detection to visualize the distance between the nerve and lead tract during the procedure to ensure millimeter-level proximity for all SNS electrodes. The planned PAV system is a combination disposable kit with the PA-based tools, used in conjunction with current SNS placement kits, and a reusable display/processing unit. Specific Aims: Aim 1. Design of PA transducers, hardware, and in vitro performance demonstration. Aim 2. Integrate deflection, confirm performance ex vivo, and complete surgical plan. Aim 3. PAV preclinical study demonstration and evaluation of minimal stimulation threshold.